#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(int argc,char*argv[])
{
    //输入字符串
    char c[100];
    scanf("%s",c);
    int i;
    int length=strlen(c);
    //检验是否是回文字符串
    int isPalindrome=1;
    for(i=0;i<length/2;i++){
        if(c[i]!=c[length-1-i]){
            isPalindrome=0;
            break;
        }
        
    }
    if(isPalindrome){
    printf("yes\n");
    }else{
        printf("no\n");
    }

    return 0;
}